Find the simplest value of:
(i) `\frac{3\sqrt{8}-2\sqrt{12}+\sqrt{20}}{3\sqrt{18}-2\sqrt{27}+\sqrt{45}}`
(ii) `\frac{4\sqrt{3}}{2-\sqrt{2}} - \frac{30}{4\sqrt{3}-\sqrt{18}} - \frac{\sqrt{18}}{3-2\sqrt{3}}`
(iii) `\frac{x+\sqrt{x^2-1}}{x-\sqrt{x^2 - 1}} + \frac{x-\sqrt{x^2 - 1}}{x+\sqrt{x^2-1}}`
(iv) `\frac{3\sqrt{7}}{\sqrt{2}+\sqrt{5}} - \frac{5\sqrt{5}}{\sqrt{2}+\sqrt{7}} + \frac{\sqrt{2}}{\sqrt{5}+\sqrt{7}}`